Increasing the sensitivity of photographic emulsions



United States Patent 3,255,013 INCREASING THE SENSITIVITY 0F PHOTOGRAPHIC EMULSIONS Fritz Dersch, Binghamton, and Sally L. Paniccia, Endwell, N.Y., assignors to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Dec. 27, 1963, Ser. No. 334,019 4 Claims. (Cl. 96-10'7) have been recommended for use for this purpose, e.g.,

condensation products of an alkylene oxide with glycols, such as those having from 8 to 18 carbon atoms as described in U.S. Patent 2,240,472 and British Patent 443,559, condensation products of alkylene oxides with amines, alcohols and carboxylic acids, that is polyalkyleneethers, esters and amides, the preparation of which is described in U.S. Patents 1,970,578 and 2,400,532.

The polyalkylene oxide or derivatives of alkylene oxide should preferably have a molecular weight of 1500 to' 4000 or more but at least that of 300.

It is also known that the use of these compounds is limited because of their tendency to increase fog during storage of the photographic film, especially storage at elevated temperatures and humidities. It is also known that it is difficult to control this fog by conventional antifoggants. Therefore, it is usual to employ special antifoggants with alkylene oxide polymers and condensation products of alkylene oxide and in this connection reference is made to U.S. Patents 2,704,716; 2,716,062 and 2,728,666.

It has now been found very surprisingly that condensation products of an alkylene oxide, i.e., ethylene oxide, propylene oxide and butylene oxide with 1,4-di-isobutyl- 1,4-dimethyl-butynediol of the formula CH CH CH3 CH3 do not portray an excessive tendency to fog silver halide emulsions and do not require the use of other than the simple, conventional antifoggants to control fog formation. The use of such products as speed increasing agents show a marked increase in density for a given exposure. Such condensation products should have a molecular weight of at least about 300 but preferably about 1,000 or more, i.e., 4,000 to 150,000 or more.

The use of such polyoxyalkylene derivatives in photographic silver halide emulsions or layers adjacent thereto as speed-increasing elements therefore constitutes the purposes and objects of our invention.

The preferred polyoxyalkylene compounds used herein have the following formula CH3 CH3 where m and n together represent'integers ensuring a molecular weight of from about 300 to 150,000 or more.

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surface coating prior to the coating operation. If desired,

they may be added during the actual preparation of the emulsion either before or after washing of the emulsion.

The quantity of the polyoxyalkylene derivative employed should range from .1 to 8 gms. per .6 mol of silver halide.

The speed increasing agents which we have described may be used in various types of photographic emulsions, e.g., non-sensitized emulsions, 'orthochromatic, panchromatic and X-ray emulsions. If used with sensitizing dyes, they may be added to the emulsion before or after the dyes are added. Various silver salts may be used as the sensitive element, such as silver bromide, silver iodide, silver chloride or mixed silver halides. The polyalkylene derivatives may be used in emulsions intended for color photography, e.g., emulsions containing colorforming components. The dispersing agent in the photographic emulsion may be gelatin, or other hydrophilic colloids, such as collodion, albumen, methyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, or the like.

The following examples will illustrate the effectiveness of the polyalkylene derivatives of our invention as speed increasing elements in photographic silver halide emulsion.

Example" I A silver halide emulsion in gelatin containing 4% silver iodide and 96% silver bromide was prepared in a conventional manner and brought up to its maximum light-sensitivity. It was then readied for coating on film base, that is, melted at 40 C., necessary coating finals were added such as sensitizing dyes, stabilizers and hardeners. A 10% aqueous solution of a condensation product of the above formula having a molecular weight of about 30,000 (Product A) was prepared and 10 cc. of this solution was added to a sample of the above described emulsion, containing about 0.4 mol of silver halide. A sample of the same emulsion, but not containing the speed increasing additive served as a control. The so-prepared emulsion samples were coated on a suitable cellulose ester base and dried. Samples of these film coatings were then exposed in a Type I-B Sensitometer, developed in a developer of the following composition:

3 Example [I A silver halide emulsion rin gelatin containing 4% silver iodide and 96% silver bromide was coated on film base in a manner known to the art. After the coating was performed, an aqueous gelatin solution containing 20 grams of gelatin per liter and 1.2 grams of a condensation product of the above formula having a molecular weight of about 500 and sold under the trademark of Surfynol 440 was coated thereon as an antiabrasion layer. After drying, film samples were exposed and processed as described in Example I. The samples described exhibited a relative speed of 175 with afog of .10 as compared with a type coating of the same emulsion having an antiabrasion layer similar to that described above, but lacking the speed increasing additive which had a speed of 100 and afog of .13.

What is claimed is: p

1. In a. photographic element a light-sensitive silver halide emulsion layer having in intimate contact therewith the condensation product of an alkylene oxide having from 2 to 4 carbon atoms with 1,4-diisobutyl-1,4-dimethyl-butyned iol, said condensation product having a molecular weight of at least 300.

2. The product as defined in claim 1 wherein said condensation product is located in said silver halide emulsion.

3. The product as defined in claim 1 wherein said condensation product is employed in an amount of from about .1 to 8 grams per .6 mol of silver halide.

4. The product as defined'in claim 1 wherein the condensation product has the following formula.

wherein m and n represent integers providing a molecular weight of at least 300.

No references cited.

' NORMAN G. TORCHIN, Primary Examiner.

I. H. RAUBITSCHEK, Assistant Examiner. 

1. IN A PHOTOGRAPHIC ELEMENT A LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYER HAVING AN INTIMATE CONTACT THEREWITH THE CONDENSATION PRODUCT OF AN ALKYLENE OXIDE HAVING FROM 2 TO 4 CARBON ATOMS WITH 1,4-DIISOBUTYL-1,4-DIMETHYL-BUTYNEDIOL, SAID CONDENSATION PRODUCT HAVING A MOLECULAR WEIGHT OF AT LEAST
 300. 4. THE PRODUCT AS DEFINED IN CLAIM 1 WHEREIN THE CONDENSATION PRODUCT HAS THE FOLLOWING FORMULA. 